Allele frequencies of AVPR1A and MAOA in the Afrikaner population

Abstract:

The Afrikaner population was founded mainly by European immigrants that arrived in South Africa from 1652.
However, female slaves from Asia and Africa and local KhoeSan women may have contributed as much as 7%
to this population’s genes. We quantified variation at two tandem repeats to see if this historical founder effect
and/or admixture could be detected. The two loci were chosen because they are in the promoters of genes
of neurotransmitters that are known to be correlated with social behaviour. Specifically, arginine vasopressin
receptor 1A’s (AVPR1A) RS3 locus has been shown to correlate with age of sexual onset and happiness in
monogamous relationships while the tandem repeat in the promoter of the monoamine oxidase A (MAOA)
gene correlates with reactive aggression. The Afrikaner population contained more AVPR1A RS3 alleles than
other Caucasoid populations, potentially reflecting a history of admixture. Even though Afrikaners have one
of the lowest recorded non-paternity rates in the world, the population did not differ at AVPR1A RS3 locus
form other European populations, suggesting a non-genetic explanation, presumably religion, for the low
non-paternity rate. By comparing population allele-frequency spectra it was found that different studies have
confused AVPR1A RS3 alleles and we make some suggestions to rectify these mistakes in future studies.
While MAOA allele frequencies differed between racial groups, the Afrikaner population showed no evidence
of admixture. In fact, Afrikaners had more 4-repeat alleles than other populations of European origin, not
fewer. The 4-repeat allele may have been selected for during colonisation.